1. Field of Invention
The invention relates to an adjustable wrench with ratchet function, and more especially to an adjustable wrench having a very small maximum clamping opening angle between the handle and the fixed jaw when reversely operating the adjustable wrench.
2. Related Prior Art
Please refer to FIG. 8, which is a perspective drawing showing the operation of a conventional adjustable wrench. First, the clamping opening 90 of the conventional adjustable wrench is fitted with a hexagonal nut 91. Then, the conventional adjustable wrench is turned clockwise to a certain angle to rotate the hexagonal nut 91 as shown in FIG. 8. However, if it it necessary to further fasten the hexagonal nut tightly, it is desired to move the conventional adjustable wrench away from the hexagonal nut 91, that is, to detach the hexagonal nut 91 from the clamping opening 90 of the conventional adjustable wrench, and then to repeat the fitting and turning process. As such, the hexagonal nut 91 can be firmly fastened or disengaged after repeating several operating processes. In other words, the conventional adjustable wrench cannot be directly turned counterclockwise; otherwise the hexagonal nut would be turned with the wrench to the original position. This causes inconveniences in operating.
Taiwan Patent No. 488338 discloses a conventional adjustable wrench, which is particularly configured with a reversible function. Specifically, the hexagonal nut in the clamping opening of the conventional adjustable wrench would not be turned back to the original position when the wrench is turning reversely. As such, the wrench would not have to disengage from the hexagonal nut after each turning stroke during fastening or unfastening the hexagonal nut. However, as shown in FIG. 9, a maximum clamping opening angle between the fixed jaw and the handle is very large, about 24 degree angle, when reversely using the conventional adjustable wrench.
FIG. 10 is a perspective drawing showing a different kind of the conventional adjustable wrench, such as disclosed in Taiwan Patent No. I340065, which has a maximum clamping opening angle between the fixed jaw and the handle. The maximum clamping opening angle is still quite large, about 10 degree angle. Taiwan Patent No. M300594 has a problem similar to those mentioned above.
Besides, some of the previously mentioned adjustable wrenches further comprise a switch member, such as the stopping post disclosed by Taiwan Patent No. 488338 and the driving member disclosed by Taiwan Patent NO. I340065, which is used to switch the conventional adjustable wrench in a traditional mode or in a ratchet mode. When the traditional adjustable wrench is in the traditional mode, the traditional adjustable wrench as shown in FIG. 8 is not allowed to turned reversely. When the traditional adjustable wrench is in the ratchet mode, they are thus allowed to turned reversely. It is noted that they are still operated in the conventional process as shown in FIG. 8 even though a user operates these traditional adjustable wrench with reversible function. However, the switch member of these traditional adjustable wrench is disposed away from a position of user's thumb when the user holds the adjustable wrench, which would cause seriously inconveniences while switching.